"Most observations and measurements of starch
granules in leaves have been made on a transmission
electron microscope (TEM) or light microscope images
of sections through mesophyll cells." And flow cytometry

Comments

"...starch
occupied an average of 15% of the chloroplast volume...Although starch occupied approximately 15% of
the volume of chloroplasts of both mature and immature
leaves at the end of the day, and daily starch
turnover was comparable, the chloroplasts of immature
leaves contained more, smaller granules than those of
mature leaves."